From c6b2c2fb577d20879b5b4c610c4c29bac259beab Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Fri, 17 Jul 2020 21:29:13 +0900
Subject: [PATCH] netlink: introduce rtnl_get/delete_link_alternative_names()

(cherry picked from commit 14982526145de84201c7e3b4fc6be6aa5e9a08f7)

Related: #2005008
---
 src/libsystemd/sd-netlink/netlink-util.c | 45 ++++++++++++++++++++++--
 src/libsystemd/sd-netlink/netlink-util.h |  2 ++
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/src/libsystemd/sd-netlink/netlink-util.c b/src/libsystemd/sd-netlink/netlink-util.c
index 62fc71a3d8..7f09261981 100644
--- a/src/libsystemd/sd-netlink/netlink-util.c
+++ b/src/libsystemd/sd-netlink/netlink-util.c
@@ -81,12 +81,45 @@ int rtnl_set_link_properties(sd_netlink **rtnl, int ifindex, const char *alias,
         return 0;
 }
 
-int rtnl_set_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names) {
+int rtnl_get_link_alternative_names(sd_netlink **rtnl, int ifindex, char ***ret) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL, *reply = NULL;
+        _cleanup_strv_free_ char **names = NULL;
+        int r;
+
+        assert(rtnl);
+        assert(ifindex > 0);
+        assert(ret);
+
+        if (!*rtnl) {
+                r = sd_netlink_open(rtnl);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_rtnl_message_new_link(*rtnl, &message, RTM_GETLINK, ifindex);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_call(*rtnl, message, 0, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_read_strv(reply, IFLA_PROP_LIST, IFLA_ALT_IFNAME, &names);
+        if (r < 0 && r != -ENODATA)
+                return r;
+
+        *ret = TAKE_PTR(names);
+
+        return 0;
+}
+
+static int rtnl_update_link_alternative_names(sd_netlink **rtnl, uint16_t nlmsg_type, int ifindex, char * const *alternative_names) {
         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
         int r;
 
         assert(rtnl);
         assert(ifindex > 0);
+        assert(IN_SET(nlmsg_type, RTM_NEWLINKPROP, RTM_DELLINKPROP));
 
         if (strv_isempty(alternative_names))
                 return 0;
@@ -97,7 +130,7 @@ int rtnl_set_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const
                         return r;
         }
 
-        r = sd_rtnl_message_new_link(*rtnl, &message, RTM_NEWLINKPROP, ifindex);
+        r = sd_rtnl_message_new_link(*rtnl, &message, nlmsg_type, ifindex);
         if (r < 0)
                 return r;
 
@@ -120,6 +153,14 @@ int rtnl_set_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const
         return 0;
 }
 
+int rtnl_set_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names) {
+        return rtnl_update_link_alternative_names(rtnl, RTM_NEWLINKPROP, ifindex, alternative_names);
+}
+
+int rtnl_delete_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names) {
+        return rtnl_update_link_alternative_names(rtnl, RTM_DELLINKPROP, ifindex, alternative_names);
+}
+
 int rtnl_resolve_link_alternative_name(sd_netlink **rtnl, const char *name, int *ret) {
         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL, *reply = NULL;
         int r;
diff --git a/src/libsystemd/sd-netlink/netlink-util.h b/src/libsystemd/sd-netlink/netlink-util.h
index ea98439fad..4fc31aa274 100644
--- a/src/libsystemd/sd-netlink/netlink-util.h
+++ b/src/libsystemd/sd-netlink/netlink-util.h
@@ -38,7 +38,9 @@ static inline bool rtnl_message_type_is_routing_policy_rule(uint16_t type) {
 
 int rtnl_set_link_name(sd_netlink **rtnl, int ifindex, const char *name);
 int rtnl_set_link_properties(sd_netlink **rtnl, int ifindex, const char *alias, const struct ether_addr *mac, uint32_t mtu);
+int rtnl_get_link_alternative_names(sd_netlink **rtnl, int ifindex, char ***ret);
 int rtnl_set_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names);
+int rtnl_delete_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names);
 int rtnl_resolve_link_alternative_name(sd_netlink **rtnl, const char *name, int *ret);
 
 int rtnl_log_parse_error(int r);
